States of Matter

Kinetic Theory of Matter

• All matter is made of molecules/atoms that act like tiny particles.

• Molecules are always in motion! The higher the temperature, the faster the particles move.

• At the same temperature, heavier particles move slower than lighter particles.

Tennis Ball/Box Demo

• Small vibrations = Solid• More Energy Added in the form of

heat energy, bouncing inside box = Liquid

• Even More Energy Added in the form of heat energy, balls falling out of box = Gas (evaporation) Heavier molecules evaporate at a slower rate.

• Putting the balls back into the box = Condensation

Why metal balls inside some of the tennis balls?

• Heavier molecules take more energy to evaporate.

• Lighter molecules evaporate more readily.

• Video – Kinetic Molecular Theory

Watch as the water molecules gain enough kinetic energy to evaporate.

How does thermal energy affect the state of a substance?

• Thermal Energy interactive Video – Investigate at home

• Video molecules in motion

Temperature• Temperature is the average kinetic energy of

the atoms (or molecules) in a system. • Temperature measures how “hot”

something is.

Temperature Scales• Fahrenheit (English system)

– Water freezes at 32⁰ F and boils at 212⁰ F. • Celsius

– freezing point of water is 0⁰ C, and boiling point is 100⁰ C.

• Kelvin (scale that is based on energy content) – At zero Kelvin (absolute zero) all molecular motion

stops. – Scientists have figured out a way to get a

temperature only a few billionths of a degree above absolute zero.

5 States of Matter• Elements and compounds can move from

one phase to another when specific physical conditions are present.

• When the temperature of a system goes up, the matter in the system becomes more excited and active.

• As the temperature rises, matter moves to a more active state.

5 States/Phases of Matter

• Bose-Einstein Condensates (BEC) • Solids• Liquids• Gases• Plasmas

Bose-Einstein Condensate• In 1995, two scientists, Cornell

and Weiman, created the condensate.

• Two other scientists, Satyendra Bose and Albert Einstein, had predicted it in the 1920s, but they didn't have the equipment and facilities to make it happen at that time.

• BECs can only be created with a few special elements. Cornell and Weiman did it with rubidium (Rb).

What is a Condensate? Think Condensation

• Condensation happens when several gas molecules come together and form a liquid. The molecules get denser or packed closer together.

• It all happens because of a loss of energy. Gases are really excited atoms. When they lose energy, they slow down and begin to collect.

• Water (H2O) vapor in the form of steam condenses on the lid of your pot when you boil water. It cools on the metal and becomes a liquid again. You would then have a condensate.

Bose-Einstein condensate (BEC) • Super unexcited and super cold atoms. • Colder than solids• Occur at temperatures near absolute 0 ((0 K,

−273.15 °C, or −459 °F ) • Atoms begin to clump - no more energy to

transfer• creating a "super atom." The atoms take on

the same qualities and become one blob – No longer separate atoms

Bose-Einstein Basics

Bose-Einstein Basics

What is a solid?

• Solids have a – definite shape – definite volume.– Molecules are tightly packed – Cannot move freely, can only vibrate – Molecules stay fairly still.– Has a stable, definite shape – Energy and temperature are very low

Solids are broadly characterized as

• Crystalline Solids- Repeating pattern ExamplesGhost crystals crystals in rocksSalt rock candyCopper Sulfate

• Amorphous Solids- - Non-repeating pattern ExamplesWax play doughhand putty peanut butterGum clay

What is a liquid?

Liquids have • no definite shape, take shape of

container in which it is held• Definite volume. • Molecules are closely packed • Molecules vibrate and slide around one

another easily.• Energy and temperature, in

comparison to a solid, are higher.

What is a Gas?• Gases have indefinite and unstable shape • No definite volume, volume determined by

container• Molecules can vibrate, slide, spin, and bounce off

of one another.• Molecules are far apart and can move around

quickly.• Energy and temperature are higher than those of

both solids and liquids.• Gases diffuse (move from higher concentrations to

lower)– Heat will increase the rate of diffusion.

What is plasma?• Charged particles --Ionized

Gas-- a cloud of protons, neutrons and electrons where all the electrons have come loose from the atoms

• This is an extreme gas! Strikes the other atoms so forcefully it knocks off an electron!

• These gases – vibrate, – Slam into one another

causing bright gases, – lots of heat – lots of energy.

• Hotter than gas! A plasma occurs when the temperature is between 1000 degrees C and 1,000,000,000 degrees C

Plasma Examples

Lightning

plasma balls

Our Sun, the core of stars

Plasma TV

Neon Signs

Plasma Cutters

Aurora Borealis

Plasma the 4th State of Matter

A Phase Change

• A "phase" describes a physical state of matter.

– If energy is added (like increasing the temperature) or if energy is taken away (like freezing something), you have created a physical change.

A Phase Change

• A compound or element can move from one phase to another, but still be the same substance.

• It may require extreme temperatures or extreme pressures, but it can be done.

http://www.wisc-online.com/objects/ViewObject.aspx?ID=GCH4204

Melting

SOLID LIQUID

•Melting Point - the temperature at which matter changes from solid to liquid, (e.g. The melting point of water from ice to liquid water is 0 °C)

Evaporation

LIQUID GAS

•Boiling a liquid to form a gas is called vaporization.

Super Heated Steam Video https://www.youtube.com/watch?v=yFnNK9fNdls

Evaporation

How does evaporation differ from vaporization?

Vaporization, Boiling, Evaporation

Boiling vs. Evaporation

Sublimation

SOLID GAS

Examples:Mothballs in closetDry ice

Condensation

GAS LIQUID

Examples:Glass of ice

waterBathroom

mirror after showerDew on grass.

Freezing or Solidification

LIQUID SOLID

Water is the only known substance that expands as it freezes. Most substances contract.

Deposition

GAS SOLID

Examples:Frost on glass-

Water vapor becoming a solid

Pressure and Phase Change

• If lowering the temperature won’t get a liquid to change to a solid just apply pressure.

• By applying pressure you are “pushing” the molecules together.

Thermal Expansion

• Thermal expansion is the tendency of a matter to change in volume in response to a change in temperature.

Examples:Sidewalk crackingBridges

Demo – Hand Boiler

Heating and Cooling Curves

• Heating Curve Link